/**
 * Given a collection of distinct numbers, return all possible permutations.
 * For example,[1,2,3] have the following permutations:
 * [
 *   [1,2,3],
 *   [1,3,2],
 *   [2,1,3],
 *   [2,3,1],
 *   [3,1,2],
 *   [3,2,1]
 * ]
 */
/**
 * @author Ivan
 *
 */
package problem46_Permutations;